I'm not sure how he turned NR off on the nx500? I'm downloading the video file now...
UPDATE: I've seen the video, well the noise is definitely there but it's there in a way that makes me think it's the sensor design that it's not good in low light. Agreed that it's 6400 but isn't the a6300 clear at that ISO? Even the Nikons at 6400 don't look that bad.